Resource use by the Eastern Grey Kangaroo and the Black Wallaby in a managed remnant woodland community

This work studies the interactions and relationships that exist between Eastern Grey Kangaroos and Black Wallabies in their utilisation of spatial and trophic resources in a managed remnant woodland community. The thesis provides a closer understanding of the way in which these species impact upon their habitats. The Coranderrk Reserve, near Healesville in eastern Victoria, Australia was the study site. A floristic analysis of the communities of the study site was conducted. This consisted of plant biomass measurements, estimates of plant abundance and cover determination. Faecal pellets from Eastern Grey Kangaroos and Black Wallabies were collected from ten vegetation communities during three different plant productivity periods. The spatial and temporal distribution of the animals was identified by analysing the frequency of occurrence of faecal pellets in the various communities. The use of faecal pellet density as a measure of habitat utilisation was examined. Eastern Grey Kangaroos utilised communities which were characterised by the presence of a dense grassy statum. Black Wallabies were able to utilise all of the communities of the study site regardless of their floristic composition. A reference herbarium of the leaf epidermis of 233 possible forage plant species was accumulated. These epidermal specimens were prepared for Confocal Scanning Laser Microscopy. The information gained was enhanced and stored digitally. Diagnostic information critical for the identification of plant epidermal fragments was assembled into a computer database. This was used to assist in the recognition of unknown epidermal fragments in macropodid faeces. These epidermal plant recognition techniques enabled a list of the contents of Eastern Grey Kangaroo and Black Wallaby faeces during the sampling periods in the individual communities, to be accumulated. Eastern Grey Kangaroos utilised forage which consisted largely of grass and their diets were similar regardless of their feeding sites or the time of the year. Black Wallaby diets were heterogenous with wide variations over space and time observed. The implications of these findings for current wildlife management practices were considered. Black Wallaby and Eastern Grey Kangaroo herbivory have significant impacts on ecosystem integrity. Management strategies should seek to establish ecologically sustainable populations of both species in remnant woodlands where conservation values are important.

Tammar wallaby mammary cathelicidins are differentially expressed during lactation and exhibit antimicrobial and cell proliferative activity

Cathelicidins secreted in milk may be central to autocrine feedback in the mammary gland for optimal development in addition to conferring innate immunity to both the mammary gland and the neonate. This study exploits the unique reproductive strategy of the tammar wallaby (Macropus eugenii) model to analyse differential splicing of cathelicidin genes and to evaluate the bactericidal activity and effect of the protein on mammary epithelial cell proliferation. Two linear peptides, Con73 and Con218, derived from the heterogeneous carboxyl end of cathelicidin transcripts, MaeuCath1 and MaeuCath7 respectively, were evaluated for antimicrobial activity. Both Con73 and Con218 significantly inhibited the growth of Staphylococcus aureus, Pseudomonas aureginosa, Enterococcus faecalis and Salmonella enterica. In addition both MaeuCath1 and MaeuCath7 stimulated proliferation of primary tammar wallaby mammary epithelial cells (WallMEC). Lactation-phase specific alternate spliced transcripts were determined for MaeuCath1 showing utilisation of both antimicrobial and proliferative functions are required by the mammary gland and the suckled young. The study has shown for the first time that temporal regulation of milk cathelicidins may be crucial in antimicrobial protection of the mammary gland and suckled young and mammary cell proliferation.

Paracrine control of milk protein gene expression in tammar wallaby

Stephen utilised the unique lactation strategy of the tammar wallaby to identify factors within the mammary gland that determine the composition of milk and how the milk composition changes throughout lactation in order to provide immunity both to the nursing mammary gland and the suckling.

Differential temporal expression of milk miRNA during the lactation cycle of the marsupial tammar wallaby (Macropus eugenii)

Lactation is a key aspect of mammalian evolution for adaptation of various reproductive strategies along different mammalian lineages. Marsupials, such as tammar wallaby, adopted a short gestation and a relatively long lactation cycle, the newborn is immature at birth and significant development occurs postnatally during lactation. Continuous changes of tammar milk composition may contribute to development and immune protection of pouch young. Here, in order to address the putative contribution of newly identified secretory milk miRNA in these processes, high throughput sequencing of miRNAs collected from tammar milk at different time points of lactation was conducted. A comparative analysis was performed to find distribution of miRNA in milk and blood serum of lactating wallaby.

Comparative analysis of caveolins in mouse and tammar wallaby: role in regulating mammary gland function.

Recent studies using the mouse showed an inverse correlation between the Caveolin 1 gene expression and lactation, and this was regulated by prolactin. However, current study using mammary explants from pregnant mice showed that while insulin (I), cortisol (F) and prolactin (P) resulted in maximum induction of the β-casein gene, FP and IFP resulted in the downregulation of Caveolin 1. Additionally, IF, FP and IFP resulted in the downregulation of Caveolin 2. Immunohistochemistry confirmed localisation of Caveolin 1 specific to myoepithelial cells and adipocytes. Comparative studies with the tammar wallaby showed Caveolin 1 and 2 had 70-80% homology with the mouse proteins. However, in contrast to the mouse, Caveolin 1 and 2 genes showed a significantly increased level of expression in the mammary gland during lactation. The regulation of tammar Caveolin 1 and 2 gene expression was examined in mammary explants from pregnant tammars, and no significant difference was observed either in the absence or in the presence of IFP.

Role of marsupial tammar wallaby milk in lung maturation of pouch young

Background: Marsupials such as the tammar wallaby (M.Eugenii) have a short gestation (29.3 days) and at birth the altricial young resembles a fetus, and the major development occurs postnatally while the young remains in the mother's pouch. The essential functional factors for the maturation of the neonate are provided by the milk which changes in composition progressively throughout lactation (300 days). Morphologically the lungs of tammar pouch young are immature at birth and the majority of their development occurs during the first 100 days of lactation. Results: In this study mouse embryonic lungs (E-12) were cultured in media with tammar skim milk collected at key time points of lactation to identify factors involved in regulating postnatal lung maturation. Remarkably the embryonic lungs showed increased branching morphogenesis and this effect was restricted to milk collected at specific time points between approximately day 40 to 100 lactation. Further analysis to assess lung development showed a significant increase in the expression of marker genes Sp-C, Sp-B, Wnt-7b, BMP4 and Id2 in lung cultures incubated with milk collected at day 60. Similarly, day 60 milk specifically stimulated proliferation and elongation of lung mesenchymal cells that invaded matrigel. In addition, this milk stimulated proliferation of lung epithelium cells on matrigel, and the cells formed 3-dimensional acini with an extended lumen. Conclusions: This study has clearly demonstrated that tammar wallaby milk collected at specific times in early lactation contains bioactives that may have a significant role in lung maturation of pouch young.

Playing a critical role: experiential learning resources and analytical media studies in higher education

This article compares two Information and Communication Technologies (ICTs) used in the Faculty of Arts, Deakin University Australia, and investigates the relationships between technology, pedagogy and key issues in the teaching and practice of public relations, in a media studies context. The online role-play ‘Save Wallaby Forest’ and the e-simulation ‘PRessure Point! Getting Framed (GF), in their different ways, afford learning  environments with capabilities that present public relations and media students with opportunities to discover a critical consciousness, break out of naturalised world-views, and explore alternative approaches to organisational communication. Furthermore, they present students with complex ethical issues to investigate based around the idea that media industries are powerful discursive producers and reproducers of social norms, values and beliefs which in turn shape notions of identity and influence the formation of public opinion in society (Fairclough 1999; Habermas 1995). This article explores the intersections and differences between these distinct ICTs in their relationships to a constructivist learning approach and ethical questions about how public relations both produces and reproduces world views through practice. This interacting nexus – between technology, pedagogy and theme – is significant because “what happens in the learning process” relates to the learning outcome and therefore has the potential to develop holistic reflexivity in studies of public relations (Laurillard 2003, p.42).

Does baiting influence the relative composition of the diet of foxes?

The changes in the diet of foxes (Vulpes vulpes) in the Jervis Bay Region was assessed following a long-term baiting program by analysing the composition of fox faecal excreta (scats). In all, 470 fox scats were collected between April and August 2003 from two baited sites, Booderee National Park (BNP) and Beecroft Peninsula, and from two unbaited sites in the southern and northern parts of Jervis Bay National Park (SJBNP and NJBNP respectively). Diet was compared between these sites and mammalian diet was also compared from scats collected before baiting in 1996 and after baiting in 2000 at Beecroft Peninsula and in 2001 at Booderee National Park. In 2003, the most common species consumed by foxes was the common ringtail possum (Pseudocheirus peregrinus), except at unbaited NJBNP, where the swamp wallaby (Wallabia bicolor) was the most frequent dietary item. Significant dietary differences were found between unbaited and baited sites, with the long-nosed bandicoot (Perameles nasuta) and P. peregrinus featuring more in the diet of foxes from the baited sites. Marked increases in the frequency of occurrence of P. peregrinus and P. nasuta in fox scats occurred from before baiting through to after baiting. Relative fox abundance, as indexed by the number of scats collected per kilometre, was lowest in Booderee, followed by Beecroft, then SJBNP, with NJBNP having the highest relative abundance of foxes. We suggest that baiting did affect the diet of foxes on both peninsulas and that the dietary changes across baiting histories were intrinsically related to an increase in abundance in some taxa as a result of relaxed predator pressure following sustained fox control. However, the lack of unbaited control sites over the whole study precludes a definitive conclusion.

Resource partitioning in sympatric populations of Red-necked Wallabies and Black Wallabies

Examines the potential for competition to occur between the Red-necked Wallaby and the Black Wallaby by examining the extent of overlap in their dietary preferences and in their utilisation of habitat at different times of the day and year. Significant separation occured between species to facilitate coexistence.

Effects of a fox removal program on small and medium-sized mammal population dynamics within the Anglesea Heathlands, Victoria

This thesis assessed the diet of foxes within the ALCOA lease area of Anglesea to determine which native and introduced species foxes were eating. Results showed that Swamp Wallaby was regularly eaten but many other mammals, birds, insects and reptiles were also consumed. The response of native mammals to seasonal fox removal was also determined.